JPH09278009A - Packaging machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively prevent a film from slipping out from a gripper by a method wherein on one of film gripping parts, a front gripper and a side gripper, which grip the discharging end of the film and the side edge part in the width direction of the film, a film contact member made of silicon sponge, is fitted. SOLUTION: After pulling out a packaging film by gripping the discharging end by a front gripper, the width of the film is widened by gripping the side edge parts in the width direction of the pulled out film by a pair of side grippers 85, 86, for this packaging machine. For such a packaging machine, to an upper clamper 88b of the side grippers 85, 86, a film contact member 100 made of a flexible silicon sponge for which silicone is formed into a sponge-form, is bonded so as to cover the lower surface of the leading end part 88a. In the meantime, a contact member 101 is bonded to a lower clamp 89 so as to cover the upper surface of the leading end part 89a. Also, a U-shaped flange 88c is formed for the upper clamper 88b to reduce a frictional resistance when the film is folded into the bottom part of a tray.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a packaging machine for automatically packaging foods and other articles contained in flat trays together with the trays using a stretchable film.

[0002]

2. Description of the Related Art An automatic packaging machine for packaging an article to be packaged together with a tray using a stretchable packaging film is known from Japanese Patent Laid-Open No. 6-32125. This wrapping machine includes a movable front gripper that holds the feeding end of the film and draws the film with respect to an article to be wrapped, and both side edges of the film that are provided in the width direction of the drawn film. It is provided with a pair of movable side grippers that grip the portion and widen the film width.

In this automatic packaging machine, a film pulled out by a front gripper is stretched in a width direction by a pair of side grippers, and the film is placed on a tray containing articles, and then the film is fed in the feeding direction (front). The tray is packaged by folding the tray from both sides along the widthwise direction and both sides along the width direction to the outer surface of the bottom of the tray.

Each of the grippers includes an upper clamper such as a flat iron plate, and an arm-shaped lower clamper rotatably arranged below the upper clamper and opened and closed with respect to the upper clamper. Rubber is attached to the upper surface of the tip of the clamper. The rubber is brought into contact with and separated from the lower surface (film contact surface) of the tip of the upper clamper as the lower clamper is opened and closed. These grippers are moved toward the side edge of the film with the lower clamper rotated downward and the space between both clampers is open, and the side edge is positioned between the upper and lower clampers. By rotating the lower clamper upward, a side edge portion of the film or the like is grasped between the clampers, and thereafter, the film is moved to the original position. Thereby, the film is drawn out or the drawn film is extended in the width direction.

In such a stretching operation or the like, the contact between the rubber and the film prevents the film from slipping out of the gripper while maintaining the gripped state of the film to enable the stretching.

In addition to the packaging machine having the above-mentioned structure, when the drawn film is stretched in the width direction, one of the pair of side grippers located on both sides of the film in the width direction cannot move, Only the other is movably installed,
There is also known a wrapping machine having a structure in which the film is stretched in the width direction by the movement, and the gripper of such a wrapping machine also has the same structure as described above.

[0007]

This type of packaging machine is used in various environments, even under conditions of high environmental humidity such as a state in which water is sprinkled on the floor of the kitchen where the packaging machine is installed. May be used. Therefore, regardless of the environmental conditions of use, in order to complete the packaging work with this type of packaging machine, the gripping state of the film at each gripper should be maintained, and the film should be prepared from the gripper when stretching. You need to make sure you don't get out. However, this point has not been given sufficient consideration in the past.

Therefore, when the film or the gripper is used in an environment where the humidity is high, or when the temperature of the environment of use causes dew condensation, the film gripped by the gripper easily slips on the rubber due to the influence of moisture. Therefore, there is a problem that the possibility of the film coming out of the gripper is increased, and that the coming out of the gripper easily causes defective packaging.

By the way, in an experiment (holding force measurement test) conducted by the present inventor on a conventional packaging machine, Table 1 described later is used.
The results shown in are obtained. This experiment was carried out with the following two steps. In the first step, a tray called C-2, that is, a tray having a length of 192 mm, a width of 108 mm, and a depth of 17 mm, is flowed vertically in the packaging machine (longitudinal direction is the insertion direction to the packaging machine), and the side gripper With the three gripper portions at the positions corresponding to the tray holding and stretching the film, the operation of the packaging machine is stopped by intentionally issuing an error signal. Second
As shown in FIG. 7, the process is performed by the three gripper parts G
(Note that G ₁ is an upper clamper and G ₂ is a lower clamper.) A spring scale W is connected to the central portion in the longitudinal direction of the sheet metal B which is connected to one end of the film F by an adhesive tape P. Then, the scale W is pulled, and the load when the film F is pulled out from the gripper portion G is measured under the environmental conditions of temperature and humidity shown in Table 1. The rubber actually used in each gripper of the conventional packaging machine was a sponge rubber made of polyurethane.

According to such a holding force measurement test, Table 1
Under the environmental conditions of Nos. 1 and 2, the film F does not come out accidentally, and under the environmental conditions of No. 3 in Table 1, the state in which the film F is about to come off is visually recognized, but barely holds the grip state. It has been confirmed that this is possible, and under the environmental conditions of environmental numbers 4 and 5, film F
Was confirmed to come out of the gripper part G. As described above, it was found that in the conventional packaging machine, the film F is likely to come out of the gripper portion G when the use environment humidity increases.

In order to improve this point, the present inventor tried to lower the humidity of the film F by blowing hot air onto the film F using a hot air blower. In such an attempt, it was found that the film could be prevented from coming off the gripper. However, since the film is heated and softens, the stretching operation by the side gripper causes
It was found that there was an adverse effect such as an increase in the rate of tearing of the film, and it was confirmed that this is not a preferable measure.

[0012] Therefore, the problem to be solved by the present invention is to obtain a packaging machine which can effectively prevent the film from slipping out of the gripper even under the use condition where the environmental humidity is high, and which can perform automatic packaging. .

[0013]

SUMMARY OF THE INVENTION The present invention is a movable front gripper that grips the payout end of an extensible wrapping film and pulls the film against the article to be wrapped; A pair of side grippers for gripping the widthwise side edge portion to widen the film width is provided, and at least one of the pair of side grippers is movably provided to widen the film width, and the extension It is premised on a packaging machine for packaging the article with the formed film.

In order to solve the above-mentioned problems, the invention of claim 1 is at least the side gripper of the front gripper and the side gripper, and of the film sandwiching portions of the grippers facing each other. A film contact member made of silicon sponge is attached to at least one of the above.

In the invention of claim 1, since the film contact member of the gripper is made of silicon sponge, the holding force of the gripper with respect to the film when the gripper grips the film is large due to the physical properties of the contact member. it can.

In order to solve the same problem, the invention of claim 2 is characterized in that the silicon sponge forming the film contact member is soft.

According to the second aspect of the invention, since the film contact member is soft, the gripper grips and holds the film so that the film contact member is more familiar with the film and a larger film holding force is obtained. Obtainable.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows the overall configuration of a packaging machine 1. The packaging machine 1 includes a frame 2 having a front panel 2a and a rear panel 2b, and a tray loading unit 3, a tray unloading unit 4, and a tray. A supply unit 5 and a film supply unit 40 are provided.

The tray loading section 3 is provided with a horizontal belt conveyor 6 penetrating the front panel 2a in the front-rear direction, and the rear portion of the conveyor 6 is arranged between the both panels 2a, 2b. The belt conveyor 6 has a plurality of endless belts 7 arranged at intervals in the width direction. On the upper surface of the front part of the conveyor 6, a tray 1 in the shape of a flat rectangular box with an open upper surface, which contains articles A to be packed, such as foods, etc.
0 (see FIG. 2 etc.) is supplied.

The tray carry-out section 4 is arranged at a position higher than the tray carry-in section 3 between both panels 2a and 2b. The tray carry-out section 4 is provided with an electric heater (not shown) inside an endless carry-out belt conveyor 14 which is horizontally provided, and folding rollers 15 which are parallel to each other are provided on the carry-in side of the conveyor 14. A plurality of carry-out rollers 16a to 16d and a cutter receiver 51 are provided in parallel with each other between the conveyor 14 and the conveyor 14. The rollers 15, 16a to 16d and the carry-out belt conveyor 14 are rotated in the same direction in synchronization by a drive mechanism (not shown).

When the packaging machine 1 is viewed in a plan view, the tray carry-out section 4 is provided so as to be continuous at a right angle to the tray carry-in section 3 via the tray supply section 5. The tray supply unit 5 is provided with a lifter 30 (see FIGS. 5 and 6) that raises the tray 10 sent to the rear of the tray loading unit 3. The lifter 30 includes a bracket 31, a plurality of support pieces 32 that are supported by the bracket 31 and can pass between the endless belts 7 of the belt conveyor 6, and a bracket 3.
And an elevating mechanism (not shown) for elevating 0. Of the support pieces 32, the other support pieces 32 except the support piece 32 at the center position in the width direction of the tray carry-in portion 3 are rotatably supported in the front-rear direction, and are normally erected by the force of a spring (not shown). Is held in a state. This tray supply section 5
The lifter 30 has a lower position in which the support piece 32 is lower than the upper surface of the endless belt 7 and faces the bottom surface of the tray 10 on the belt 7, and a lift position in which the tray 10 is pushed up to the same height as the tray unloading section 4. It is designed such that it can be lifted and lowered.

The film supply unit 40 is provided below the tray unloading unit 4. The supply unit 40 includes a reel 41 on which a transparent and stretchable flexible film F is wound.
And a tension roller 43 for guiding the film F drawn from the reel 41, guide rollers 44a and 44b for guiding the film F guided by the roller 43, and a dispenser 46 (see FIG. 3). The guide rollers 44 a, 44 b and the comb-shaped dispenser 46 wider than the width of the film F are both supported by the frame 2.

Further, the film supply section 40 includes a grip roller 47 which can be brought into contact with and separated from the folding roller 15 from below.
A pair of levers 48 a and 48 b (see FIG. 2) that includes (see FIG. 3) and supports both ends of the roller 47 are rotatably attached to the frame 2. Both levers 48a, 4
8b is biased upward by a spring (not shown), and is held at a position in contact with the folding roller 15 by this bias. Further, the levers 48a and 48b are provided with a bent portion 49 in an intermediate portion thereof, and the bent portion 49 is rotated to a position where the grip roller 47 is in contact with the folding roller 15, and the roller support frame 13a of the tray carry-out portion 4 is provided. , 13
It is adapted to be projected above b.

Reference numeral 50 in FIG. 3 denotes a cutter which is arranged below the cutter receiver 51 and is movable up and down. This cutter 5
0 is moved up and down by a cutter driving mechanism such as an electromagnetic solenoid (not shown) between a film cutting position in which the tip is inserted into the cutter receiver 51 so as to project upward from the dispenser 46 and a standby position in which the dispenser 46 is retracted downward. The film F drawn from the reel 41 is cut by this operation.

As shown in FIG. 1, the front panel 2a
A slider 55 arranged above the tray supply unit 5 is horizontally stretched between the rear panel 2b and the rear panel 2b. Both ends of the slider 55 are supported so as to be slidable in a direction in which the guide rail 56 (only one of which is shown) 56 attached to both panels 2a and 2b is used as a guide so as to come in contact with and separate from the tray unloading section 4. The slider 55 is reciprocally moved by a drive unit 57 having a motor between a first position adjacent to the tray unloading section 4 and a second position away from the tray unloading section 4.

As shown in FIG. 3, the slider 55 pushes the tray 10 that has been pushed up to the raised position to push the tray 10 out.
And a pressing plate 58 for feeding the tray 1 to the tray 1 when the slider 55 is moved to the first position.
The folding plate 59 is provided so as to enter below 0 and contact the bottom surface of the tray 10.

A fork 62 is rotatably supported by the slider 55 via a pivot shaft 63.
An upper clamper 64, which is positioned directly below the folding plate 59, is provided so as to project toward the tray unloading section 4. The upper clamper 64 supports the roller 65 at its tip. An arm 67 is fixed to the pivot shaft 63, and a comb-shaped lower clamper 68 facing the upper clamper 64 from its lower side is attached to the arm 67.
The lower clamper 68 is biased upward by a leaf spring 69. The film F is equipped with these clampers 64 and 68.
Front gripper 7 that grips and pulls out the feeding end F ₁ of
0 is formed.

Further, cam surfaces 8 are provided on both ends of the slider 55.
2 is provided with a lever pressing member 81. The cam surfaces 82 of these members 81 come into contact with the bent portions 49 of the levers 48a and 48b when the slider 55 is slid to the first position, and the levers 48a and 48b are moved downward against a spring (not shown). The grip roller 47 is rotated so that the grip roller 47 is separated downward from the folding roller 15.

The front gripper 70 includes a slider 5
When the frame 5 is brought closer to the first position, the frame 2
It engages with a first cam (not shown) supported by the lower clamper 68, and this cam causes the lower clamper 68 to perform an opening operation to separate from the upper clamper 64. Then, when the slider 55 reaches the first position, the lower clamper 68 and the upper clamper 64 of the front gripper 70 are aligned with each other, whereby the feeding end portion F of the film F is obtained.
₁ is gripped by the front gripper 70.

As shown in FIG. 2, the tray supply section 5 is provided with a pair of side grippers 85 and 86. These grippers 85 and 86 grip the side edges F ₂ and F ₃ in the width direction of the film F fed to the tray supply section 5, and are arranged on both sides of the film F in the width direction. At the same time, they are supported so as to be movable in a direction in which they approach and separate from the frame 2. These grippers 8
Reference numerals 5 and 86 are designed to be moved in opposite directions in synchronization with each other by a gripper drive mechanism including a motor (not shown).

As shown in FIG. 4, the side gripper 8
5 and 86 are an upper clamper 88 and a lower clamper 89.
And a cam 90, a lever 91, a coil spring 92, etc., and is composed of a group of gripper portions arranged in parallel as described below.

The cam 90 is provided on the fixed base 93 so as to project therefrom.
The upper clamper 88 is formed by bending downward protruding pieces 88b (only one is shown) from both side edges of the central portion of a horizontal clamper base, and horizontally extending the shaft 9 between the distal ends of these protruding pieces 88b.
4, a roller 95 as a cam follower is rotatably attached. Then, the upper clamper 88
Is brought into rolling contact with the cam surface 90a of the cam 90, and by the coil spring 92 installed between the screw receiving pin 96 attached to the fixed base 93 and the shaft 94, it is combined with the cam 90 by the spring force of the coil spring 92. The clamper base is provided so as to always maintain a horizontal posture.

The lower clamper 89 is disposed below the clamp base and passes between the pair of projecting pieces 88b, and
The pair of projecting pieces 88b are pivotally supported by a shaft 97 so as to be rotatable. The lower clamper 89 has an end (film sandwiching portion) 89a farther from the cam 90 than the upper clamper 8.
It is adapted to be brought into contact with and separated from the tip portion (film holding portion) 88a of the No. 8 portion.

A lever 91 is rotatably supported on a pivot shaft 98 projecting from the side surface of the cam 90. A lever 91 for opening and closing the lower clamper 89 with respect to the upper clamper 88 has a finger 91a.
Is engaged with a pin 99 provided on the other end of the lower clamper 89.

Since the upper clamper 88 receives the upward force by the coil spring 92, the gripper portion having such a structure moves up and down as shown in FIG. 4A when the lower end portion of the lever 91 is in the upper position. The clampers 88 and 89 remain closed. Also, from this state, the lever 9
When the lower end of 1 is rotated to the lower position as shown in FIG. 4 (A), the fingers 91a and the pin 99 catch each other, so that the entire lower clamper 89 rotates counterclockwise in FIG. The upper clamper 88 is pushed against the coil spring 91 along with the rotation. In this case, since the downward displacement amount due to the rotation of the lower clamper 89 is larger than the lowering amount of the upper clamper 88, the upper and lower clampers 88 and 89 are held in the open state as shown in FIG. 4B. To be done. Further, when the lever 91 is returned upward from this open state, the upper clamper 88 is raised by the spring force of the coil spring 92, and the lower clamper 89 is rotated about the shaft 97 in the clockwise direction in FIG. , Both clampers 88, 89 as shown in FIG.
Is to be closed.

A procedure for wrapping the tray 10 containing the articles A with the film F in the wrapping machine 1 having the above-described structure will be described with reference to FIGS.

With the support piece 32 of the lid 30 waiting in the lowered position, the tray 10 containing the articles A is supplied to the tray carry-in section 3, so that the tray 10 is belted as shown in FIG. 5 (A). It is supplied to the tray supply unit 5 via the conveyor 7. Then, the slider 55 is moved toward the first position as shown in FIG. 5 (B).

Thereby, first, the grip roller 4
After 7 is largely separated below the folding roller 15, the front gripper 70 moves the tray feeding section 5 of the tray unloading section 4.
This gripper 7 is located below the end on the side.
The upper and lower clampers 64 and 68 of 0 are separated from each other and face the dispenser 46. When the slider 55 reaches the first position, the lower clamper 68 is rotated upward, and the upper clamper 64 and the lower clamper 68 rotate the dispenser 4 together.
The unwinding end portion F ₁ of the film F unwound from 6 is clamped from above and below.

Next, as shown in FIG. 5C, the slider 5
5 is slid to a second position corresponding to the size of the tray 10. Then, since the grip roller 47 is rotated upward and the film F is sandwiched between the folding roller 15 and the folding roller 15, the film F is pulled between the rollers 15 and 47 and the front gripper 70 and has an appropriate tension. And is pulled out and arranged on the tray supply unit 5. When the film F is pulled out in this way, the side grippers 85 and 86 are held at positions apart from the side edges F ₂ and F _{3 in} the width direction of the film F as shown in FIG. 6A.

After this, as shown in FIG. 6B, the side grippers 85 and 86 first open the upper and lower clampers 88 and 89 by the downward rotation of the lever 91, and then hold that state. The grippers 85 and 86 are advanced so that they approach each other, and the upper and lower clampers 88 and 89 are closed by the upward rotation of the lever 91 at this advanced position. As a result, the side edge portions F ₂ , F ₃ of the drawn film F are
Grab each individually.

Next, the side grippers 85 and 86 are set to the positions shown in FIG.
As shown in (C), the trays are moved in directions away from each other according to the width of the tray 10. As a result, the film F drawn out as shown in FIG. 2 is pulled from both sides along the width direction, and is stretched to a size sufficient to cover the tray 10 from above.

After this, as shown in FIGS. 5D and 6D, the tray is lifted through the lifter 30 and the tray 10 and the article A therein are pressed against the greatly stretched film F. Then, the film F is placed on the tray 10.

When the raising of the tray 10 is completed,
As shown in FIG. 6 (E), the side grippers 85 and 86 are advanced toward each other to enter the lower part of the tray 10, and the side edges F ₂ and F _{3 in} the width direction of the film F are the outer surface of the bottom of the tray 10. Folds along. After that, the side grippers 85 and 86 are opened to be separated from the side edge portions F ₂ and F _{3 of the} film F, and are moved in the directions away from each other, thereby returning to the initial state shown in FIG. 6 (F). To do. By such an operation, the film F drawn out to the tray supply unit 5 is folded into the bottom surface of the tray 10 from both sides along the width direction.

Next, as shown in FIG. 5 (F), the slider 55 is slid toward the first position, so that the folding plate 59 enters the bottom side of the bottom of the tray 10.
As a result, the feeding end portion F ₁ of the film F gripped by the front gripper 70 is folded back along the outer surface of the bottom portion of the tray 10 by the folding plate 59.

Then, as the slider 55 is further slid, the tray 10 is sent toward the tray unloading section 4 by the pressing plate 58, and the folding roller 15 and the unloading roller 16a ... 16d
Ride on. Then, the unwinding direction of the unrolled film F is reversed so as to wind around the folding roller 15, and the film F is folded back so as to be guided between the folding roller 15 and the carry-out rollers 16 a to 16 d and the bottom surface of the tray 10.

Next, as shown in FIG. 5G, the cutter 50 is used.
Is raised and the film F is cut. This film F
The cut end portion F4 of the sheet is obtained on the peripheral surface of the feed roller 15 and guided to the bottom surface of the tray 10. In this way, the series of packaging operations of the tray 10 with the film F is completed.

The packaged tray 10 has a rotating folding roller 15 and unloading rollers 16a-1.
6d reaches the carry-out conveyor 14, where it is heated from below. As a result, the overlapping films F on the bottom surface of the tray 10 are brought into close contact with each other, and the film F is prevented from coming off the tray 10.

By the way, in the packaging machine which repeats a series of packaging operations as described above, the holding force of the grasped film F is increased on the surface of the front gripper 70 and the side grippers 85, 86 for grasping the film F. The following configuration is adopted in.

That is, as shown in FIG. 3, in the front gripper 70, the film contact member 100 having a thickness of 1 mm is adhered to the lower surface of the upper clamper 64 at the front end side, and the film is contacted to the upper surface of the lower clamper 68 at the front end side. Film contact member 101 having a thickness of 4 mm along the shape of a comb tooth
Is glued down. In addition, this front gripper 7
Since 0 draws out the film F, a large pull-out force does not act at that time, and when the film F is stretched in the width direction, the influence is small and a large pull-out force does not act. Therefore, the film contact members 100 and 101 made of the materials described below may be omitted, and instead, a conventional sponge rubber made of polyurethane may be provided.

In the side grippers 85 and 86 as shown in FIG. 4 as a representative, a film contact member 100 having a thickness of 1 mm is adhered to the upper clamper 88 so as to cover the lower surface of the front end portion 88a serving as a film holding portion. In addition, a film contact member 101 having a thickness of 4 mm is adhered to the lower clamper 89 so as to cover the upper surface of the front end portion 89a as the film holding portion.

The upper clamper 88 is provided with a U-shaped flange 88c surrounding the periphery of the film contact member 100 fixed to the upper clamper other than the edge on the protruding piece 88b side. It is bent with a greater height than. By providing such a flange 88c, when the film F is gripped, the film F is also brought into contact with the flange 88c, and the frictional resistance with the film contact member 100 when the film F is folded into the outer surface of the bottom of the tray 10 is reduced. are doing. Thereby, the operation of returning the side grippers 85, 86 to the original standby position after the side edges F ₂ , F ₃ are folded into the outer surface of the bottom of the tray 10 during the film packaging operation is performed on the folded film F. The movement is made easy by not disturbing as much as possible. Although not shown, the upper clamper 64 of the front gripper 70 has the same device.

As the grippers 70, 85, 86 are opened and closed, the film contact members 100, 101 facing each other can come into contact with and separate from each other. And these contact members 10
Each of 0 and 101 is made of a hard or soft silicon sponge formed by molding silicon into a sponge shape. Hard silicone sponge has a hardness of 40 ° and soft silicone sponge has a hardness of 20 °.

Such film contact members 100, 101
1 with each gripper 70, 85, 86 having
Table 1 below shows the results of the holding force measurement test described above in the conventional section. For comparison, Table 1 also shows conventional ones.

[0054]

[Table 1]

As is clear from Table 1, even if both the operating environment temperature and the humidity of the packaging machine 1 rise, the gripping force of the grippers 70, 85, 86 on the film F is such that the rubber is used as the film contact member. It has been found that it is possible to exhibit a holding force that is almost double that of the conventional one.

It was also found that the soft silicon sponge has a better holding force for the film F than the hard silicon sponge. It is considered that this is because the soft silicon sponge is more familiar to the film contact members 100 and 101 when the film F is gripped and held.

Then, the packaging test was carried out by vertically flowing the tray of C-2 in the packaging machine 1 having the above-mentioned structure under the following usage environment.

The first use environment in this packaging test is that the ambient temperature is 20 ° C. and the ambient humidity is 80%. In this case, normal packaging can be performed for all 50 samples.
There was no escape of the film F that it gripped at each gripper 70, 85, 86. In addition, the film F was not torn due to the packaging. In addition, the same results as when using the tray of C-2 in the packaging test conducted in the same use environment using a tray of size C-3 (length 250 mm, width 150 mm, depth 22 mm). Got

The second use environment in the packaging test is that the ambient temperature is 20 ° C. and the ambient humidity is 85%. In this case, normal packaging can be performed for all 50 samples.
There was no escape of the film F that it gripped at each gripper 70, 85, 86. In addition, the film F was not torn due to the packaging. In addition, the same result was obtained in the packaging test performed in the same use environment using the C-3 tray.

The third environment for use in the packaging test has an ambient temperature of 35 ° C. and an ambient humidity of 50%. In this case, normal packaging can be performed for all 50 samples.
There was no escape of the film F that it gripped at each gripper 70, 85, 86. Moreover, the tear of the film F was seen about 2 to 4 packages among 50 packages. Note that C
The same result was obtained in the packaging test conducted using the tray of No. -3 in the same use environment.

For comparison, the side gripper 8
Sampelka (trade name) only on upper and lower clampers of 5, 86
Polyethylene, which is commonly referred to as "film contact member", is attached to the upper clamper without attaching anything, and the place where the contact member is contacted / separated (film holding part) is mirror-finished. , 80% environmental humidity
A packaging test was conducted in the above-mentioned use environment. As a result, in all the packages, the film F slipped out from both grippers 85 and 86, and packaging defects occurred.

For a similar comparison, the side gripper 8
A packaging machine in which velvet (commonly known as "Bechin") is attached to the lower clamper of 5,86 as a film contact member, and polyurethane sponge rubber is attached to the upper clamper in an environment where the ambient temperature is 18 ° C and the ambient humidity is 75%. A packaging test was done. As a result, in all the packages, the film F slipped out from both grippers 85 and 86, and packaging defects occurred.

For the same comparison, a wrapping machine in which cloths commonly called Synthelina (trade name) are attached as film contact members to both upper and lower clampers of the side grippers 85 and 86 at an environmental temperature of 20 ° C. A packaging test was performed in a usage environment of 80% humidity. As a result, in all the packages, the film F slipped out from both grippers 85 and 86, and packaging defects occurred.

Further, for the same comparison, a sandpaper was attached to the upper clampers of the side grippers 85 and 86 as a film contact member, and a polyurethane sponge rubber was attached to the lower clamper. A packaging test was performed in a use environment at 10 ° C. and an ambient humidity of 50% or less. As a result, sandpaper meshes number 400 and 600
In the No. 1 film, the film F never escaped from both grippers 85 and 86, but instead, the film F frequently broke. Also, with the sandpaper mesh Nos. 800 and 2000, the tear of the film F disappeared, but instead of both the grippers 8 for all the packaging.
The film F slipped out from Nos. 5 and 86, and a packaging defect occurred.

Therefore, as the film contact members 100, 101 used for the grippers 70, 85, 86 are made of silicon sponge as clarified in the above-mentioned packaging test, the unwinding end of the film F in the packaging operation. Film F pulled out when grasping and pulling out F ₁
When gripping the side edge portions F ₂ and F ₃ of the sheet and extending it in the width direction, when pressing the tray 10 containing the article A against the lower surface of the extended tray 10, and the like, the grippers 70, 85, 8
The film F grasped by 6 does not come out, so that the tray 10 can be properly packaged, and the film F can be extremely rarely torn at that time.

The present invention is not limited to the first embodiment. For example, the film contact member made of silicon sponge used for at least the side grippers 85, 86 of each of the grippers 70, 85, 86 may be only the film contact member 100 bonded to the upper clamper. This is because when the film is folded onto the outer surface of the bottom of the tray, the upper clamper is mainly in contact with the film and the lower clamper is not substantially in contact with the film. Even with these measures, at least the side grippers 85 and 86 can increase the holding force with respect to the film held and held by the film F to solve the problem of the present invention. Further, the film F is generally provided with an antifogging agent (used to clearly show the inside of the tray in a packaged state) by coating on the inner surface of the film. Although it becomes a slippery factor with respect to the grippers 85 and 86, the desired film holding force can be obtained by providing the film contact member 100 on the upper clamper. Further, in this case, the portion of the lower clamper that is brought into contact with and separated from the film contact member 100 is formed of a metal mirror-finished film contact surface or a soft vinyl chloride film sandwiching surface whose surface is almost mirror-finished. do it.

Further, since the maximum extraction force acts on the film when it is stretched in the width direction, the present invention may be carried out by providing a film contact member made of silicon sponge only for the side gripper. .

[0068]

The present invention is embodied in the form described above and has the following effects.

According to the first aspect of the present invention, since the gripper has a large holding force for the film in a state where the gripper holds the film, the packaging is performed even if the environmental humidity is high and the influence of moisture due to dew condensation is large. It is possible to prevent the film from slipping out of the gripper during the operation, which allows the automatic packaging work to be completed.

According to the second aspect of the present invention, since the gripper has a good familiarity with the film contact member with respect to the film when the film is gripped and held, a larger holding force can be obtained and the automatic packaging work can be completed. .

[Brief description of drawings]

FIG. 1 is a perspective view showing an overall configuration of a packaging machine according to a first embodiment of the present invention.

FIG. 2 is a plan view showing a state in which a tray containing articles is pressed against a film in the packaging machine according to the first embodiment.

FIG. 3 is a cross-sectional view showing a state in which a front gripper grips and pulls out a film in the packaging machine according to the first embodiment.

FIG. 4A is a sectional view showing a structure of a side gripper of the packaging machine according to the first embodiment in a closed state. (B) Sectional drawing which shows the structure of the side gripper of the packaging machine which concerns on 1st Embodiment in an open state.

5 (A) to (H) are schematic views showing a procedure for folding back a fed film from both sides along the feeding direction toward the bottom side of the tray.

FIG. 6A to FIG. 6F are schematic views showing a procedure of folding back a fed film from both sides in the width direction toward the bottom side of the tray.

FIG. 7 is a perspective view showing a structure for measuring a holding force with respect to a film held by a side gripper.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wrapping machine, 10 ... Tray, 70 ... Front gripper, 64 ... Upper clamper, 68 ... Lower clamper, 86, 87 ... Side gripper, 88 ... Upper clamper, 88a ... Tip of upper clamper (film holding portion), 89 ... lower clamper, the tip of the 89a ... lower clamper (film holding portion), 100, 101 ... the film contact member, F ... film, feeding end of the F ₁ ... film, F _2, F ₃ ... side edge portion of the film.

Claims (2)

[Claims] 1. A movable front gripper for gripping a feeding end of an extensible packaging film and pulling the film with respect to an article to be packed, and a widthwise side edge of the pulled-out film. With a pair of side grippers that widen the film width, at least one of the pair of side grippers is movably provided to widen the film width, and the article is wrapped with the stretched film. In the packaging machine, at least one of the front gripper and the side gripper, which is the side gripper, has a film contact member made of a silicon sponge attached to at least one of the opposing film holding portions of the gripper. A packaging machine that is characterized by 2. The packaging machine according to claim 1, wherein the silicone sponge forming the film contact member is soft.